The present invention relates to surface-emitting type semiconductor lasers and methods for manufacturing the same, optical modules, and light transmission devices.
Surface-emitting type semiconductor lasers are attracting attention in the field of optical communications as low cost and high performance light sources. When surface-emitting type semiconductor lasers are used for optical communications, there are cases where it may be desirous to obtain a laser beam with a radiation pattern having a narrow radiation angle.
For example, Japanese Laid-open Patent Application 2000-67449 proposes a method for forming a micro lens by an ink jet method on a laser beam emission surface of a single crystal silicon layer to thereby narrow the radiation angle. In this case, because the transverse mode is defined by an oxidized constricting layer, the number of optical modes would increase if a large current is to be injected by expanding the constricting aperture.
[Patent Document 1] Japanese Laid-open Patent Application 2000-67449